KR0168325B1 - High impact polystyrene containing low molecular weight brominated polystyrene - Google Patents

Abstract

An effective amount of low molecular weight brominated polystyrene provides unexpectedly good property retention and achieves even more desirable flame retardancy, such as UL-94 VO in high impact polystyrene. In contrast, high molecular weight brominated styrene polymers (polymerization degree of 2,000) do not provide good specific preservation such as impact strength and toughness in high impact polystyrene. Typically, the degree of polymerization of the brominated polystyrene of the present invention is about 3 to about 20 and can have a significant amount of change in the halogenation reaction. High impact polystyrene blended with low molecular weight brominated polystyrene can be readily processed by conventional equipment.

Description

[Name of invention]

High impact polystyrene containing low molecular weight brominated polystyrene

[Field of Invention]

The present invention relates to the use of low molecular weight brominated polystyrene in high impact polystyrene, in which good flame retardancy is achieved and excellent property of property retention including impact strength is provided.

Background Technology

When used in high impact polystyrene, brominated polystyrene having a degree of polymerization of about 2,000 provides excellent flame retardancy and stability but has a very negative effect on important physical properties such as impact strength. This effect is usually not allowed.

U.S. Patent No. 3,075,944 relates to flame retardant compositions containing polyolefins which can be prepared by substituting diaromatic or aromatic-aliphatic ethers containing three or more bromine atoms.

US Pat. No. 3,830,766 relates to acrylonitrile-butadiene-styrene (ABS) polymers which are refractory by incorporating aromatic bromine compounds, antimony trioxide or antimony oxychloride and optionally organic chlorine compounds.

US Pat. No. 3,897,373 relates to thermoplastic molding compositions based on styrene polymers and refractory to organic bromine compounds. They contain synergistic azo compounds and can be converted into self-extinguishing shaped articles or release articles.

U. S. Patent No. 3,943, 195 relates to thermoplastic molding materials based on olefin polymers and styrene polymers refractory to organic bromine compounds. Polymers or brominated oligomers of dialkylbenzenes, trialkylbenzenes or tetraalkylbenzenes act as fireproofing agents. The molding material may be processed into a self-extinguishing molded article.

US Pat. No. 3,962,164 discloses refractory acrylonitrile-butadiene-incorporating certain mono- and difetyl aliphatic bromine compounds, such as octabromodiphenyl, antimony trioxide, or antimony oxychloride and optionally organic chlorine compounds. Styrene (ABS) polymer.

US Pat. No. 4,049,622 relates to thermoplastic molding compositions based on styrene polymers, preferably molded sen polymers, refractory to organic bromine compounds.

US Pat. No. 4,074,032 relates to a process for preparing thermally stable brominated oligo-styrene in the presence of Lewis acid at about −25 ° C. to 20 ° C. and optionally by brominating the halogenated oligo-styrene in a halogenated solvent. Brominated oligomers are very thermally stable and can be produced in a variety of shaped articles by treatment as such or as a component of a mixture with other thermoplastics.

US Pat. No. 4,107,231 relates to refractory linearized polyethers containing halogenated oligomeric styrene and synergistic compounds as refractory.

U. S. Patent No. 4,137, 212 relates to refractory nylon molding compositions which can be treated by thermoplastic methods and contain 5-30% by weight of brominated styrene oligomers and synergistic metal oxides as fire retardants. The composition can be used to make injection molded articles for the electrical industry.

US Pat. No. 4,143,221 discloses bromine-containing styrene polymers prepared by cationic polymerization of monomers, or monomers with isobutylene or copolymerizable monomers of the alkylated styrene type in an organic solvent in the presence of a Lewis acid catalyst or It relates to a copolymer. Thereafter, bromine is added to the solution without first treating the subsequent product. The catalyst used for the bromination reaction is the same as that used for the polymerization reaction. If necessary, fresh catalyst may be added before the bromination reaction. After the bromination is complete, the reaction solution is extracted with water until bromine is liberated and the solvent, typically halohightrocarbon, is removed. Products containing up to about 80 weight percent bromine can be obtained. The product is pale yellow and no significant decomposition takes place below 340 ° C. The product can be used as a fireproofing agent for thermoplastics.

U. S. Patent No. 4,151, 223 relates to fibers and filaments of linear thermoplastic polyesters containing halogen-containing refractory agents and synergists, wherein the refractory agents are chlorinated and / or brominated oligomeric styrenes. The fibers and filaments of the invention are used in the manufacture of fibers with low flammability.

U.S. Patent No. 4,200,702 is an effective fireproofing agent that is sufficiently stable to heat, can be processed on a conventional machine, does not produce a coating on the machine, does not corrode, and does not substantially adversely affect the impact strength of the polymer. A thermoplastic molding composition based on a rubber modified styrene-acrylonitrile copolymer containing halogenated styrene oligomers. The refractory agent typically has a degree of polymerization of 3 to 200 and can be incorporated into the polymer by conventional methods. Thus, the polymer may or may not contain additional synergists and processing aids, incorporated in conventional amounts, according to conventional methods.

U.S. Patent No. 4,360,455 describes a brominated oligomer type having a low molecular weight brominated aromatic compound having a degree of polymerization of 3 to 400 and a diphenyl ether type, obtained by polymerizing an unbrominated starting material in a halohydrocarbon solvent using a Lewis acid catalyst. It relates to a mixture of polystyrene. The reaction mixture is then brominated, extracted with water to remove hydrogen bromide and the catalyst, and the solvent and volatile components are separated from the product. The bromination reaction is carried out at -30 ° C to 130 ° C. The final mixture has a low melt viscosity and is therefore particularly suitable for incorporation into thermoplastics as a fire retardant.

US Pat. No. 4,352,909 to Barda et al. Describes the reaction of high molecular weight polystyrene with bromine chloride in the presence of catalytic amount of Lewis acid, under substantially anhydrous conditions, and in chlorinated hydrocarbon solvents to produce trihalogenated polystyrene flame retardants for synthetic resins. It is about how to.

German Patent Publication No. 151,075 relates to a self-extinguishing polystyrene composition containing brominated oligomers of alpha methyl-styrene as a fire retardant with minimal loss of mechanical properties. The oligomer contains 40-70% by weight of ring bonded bromine and has a molecular weight of about 1,000 to about 5,000.

[Summary of invention]

The molecular weight of the brominated low molecular weight polystyrene is that when the polystyrene is blended with high-impact polystyrene (HIPS), it provides unexpectedly excellent physical property retention properties and provides excellent or excellent flame retardancy, such as UL-94 VO at ⅛ inch thickness. It is also an important factor in the property retention properties in that it is achieved. Low molecular weight brominated polystyrenes of the present invention generally contain from about 53 to about 76% by weight of halogenated inclusions, such as bromine, having a degree of polymerization of about 3 to about 20.

Detailed description of the invention

High impact polystyrenes are commercially available and are well known in the art as well as in the literature. High impact polystyrene (HIPS) is made from styrene monomers together with elastomers and is typically available in several grades of impact strength. HIPS is typically produced by introducing an elastomer, such as polybutadiene, into a polystyrene matrix for impact deformation, and is prepared by suspension or more preferably by mass continuous polymerization.

The low molecular weight brominated polystyrene of the present invention is an oligomer and has a degree of polymerization, ie, the number of repeating units is about 3 to about 20, typically about 5 to about 15, preferably about 6 to 12, more preferably about 7 to about 9 . Typically, repeating units have the general formula:

Halogen X, such as bromine, is present at about 1.5 to about 4.0 moles per repeat unit. The amount of bromine is typically from about 53 to about 76 weight percent, preferably from about 61 to 71 weight percent, more preferably from about 66 to about 70 weight percent, based on the total weight of each repeating unit. The molecular weight distribution of the oligomer is usually as accurate as 4.0 or less, preferably 2.5 or less.

When low molecular weight brominated polystyrene is used as the fire retardant, impact retention properties are a function of molecular weight and degree of bromination. As the molecular weight increases, the impact retention properties will be relieved at certain bromine levels. Conversely, as the bromine content incorporated with polystyrene increases, the impact retention properties will be reduced at defined or constant molecular weights. Therefore, in order to optimize the property retention properties, the above factors should usually be considered.

The low molecular weight brominated polystyrene oligomers used are generally present in effective amounts, so that good flame retardancy is achieved. That is, an effective amount of a low molecular weight brominated polymer is used, in particular when compared to a high molecular weight brominated polystyrene having a degree of polymerization of about 2,000, it has an excellent flame retardancy as an unexpected result, and an amount such that effective or excellent impact retention characteristics are obtained. it means. Effective levels of flame retardancy will be VO, for example, in inch thickness UL-94. Notable properties of the physical property include notched lzod, impact strength measured by Reverse lzod, Gardner lmpact and elongation.

An effective amount of the brominated polystyrene oligomers of the present invention is typically from about 3 to about 20 weight percent, preferably from about 10 to about 18 weight percent, more preferably from about 14 to about 20, based on the total weight of the high impact resistant polystyrene and oligomer About 16% by weight.

Compositions of the present invention that can be easily mixed and processed on conventional equipment such as extruders, banburys, two-roll mills, and the like, do not cause mold contamination and are non-fragmentable. Blending generally occurs at temperatures above the melting point of HIPS, such as about 250 ° F to 500 ° F.

The mixtures of the present invention may contain customary amounts of conventional additives as known in the art as well as the literature. For example, HIPS may contain several conventional ultraviolet light inhibitors, various lubricants such as calcium stearate, and the like. Additives commonly used due to low cost and effective flame retardant properties include various antimony-based synergists, their equivalents, derivatives thereof, and the like, and antimony trioxide. The amount of antimony based synergist is generally used at about 1 part by weight per 2 to 5 parts by weight of brominated polystyrene, based on the weight of the brominated polystyrene. Various additives and flame retardants such as antimony trioxide are added directly to HIPS and blended with HIPS, and then the mixture is blended with low molecular weight brominated polystyrene, or alternatively with low molecular weight brominated polystyrene and blended together, followed by HIPS Blend Blends of the present invention are generally VO in flame resistance 성 이 inch UL-94. Typically, certain conventional mixing devices such as extruders, banburys, two-roll mills can be used. The blends of the present invention can be used wherever flame retardant HIPS is required, such as small devices, television cabinets, computer housings and the like.

The present invention will be better understood with reference to the following examples.

EXAMPLE

Footnotes to Examples 1-8

PS: Polystyrene

DP: degree of polymerization which defines the polymer chain length by the number of repeating units in the chain

Pyro Check 68 PB: Brominated polystyrene with a DP of 2,000 and a bromine content of generally about 66.5% by weight.

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Several examples have demonstrated that low molecular weight brominated polystyrenes have much better physical properties than high molecular weight polystyrenes such as fatigue check 68 PB. Example 2 generally demonstrates that increasing the degree of polymerization of brominated polystyrene results in a decrease in property retention properties such as notched izods. Examples 3 to 7 are obtained by using the low molecular weight brominated polystyrene of the present invention as compared to the high molecular weight brominated polystyrene, as well as excellent physical property retention properties, as well as using various high-impact polystyrenes produced by other manufacturers with excellent physical property retention properties. Prove that also obtained.

Although the best mode and preferred embodiment have been mentioned above according to the invention, the scope of the invention is not limited thereby, but by the scope of the appended claims.

Claims (20)

A flame retardant high impact resistant polystyrene composition comprising high impact resistant polystyrene, an effective amount of low molecular weight brominated polystyrene to provide property retention properties, and 1 part by weight of antimony based synergist per 2 to 5 parts by weight of brominated polystyrene. The polystyrene composition of claim 1, wherein the low molecular weight polystyrene has a degree of polymerization of 3 to 20. The method of claim 2, wherein the halogen is bromine and the amount of bromine is 53 to 76% by weight based on the total weight of the low molecular weight polystyrene, and the amount of the low molecular weight brominated polystyrene is based on the total weight of the brominated polystyrene and the high impact resistant polystyrene. Polystyrene composition, characterized in that 3 to 20% by weight. The polystyrene composition according to claim 3, wherein the amount of low molecular weight brominated polystyrene is 10 to 18% by weight, the amount of bromine is 61 to 71% by weight, and the degree of polymerization is 5 to 15. The polystyrene composition according to claim 4, wherein the polymerization degree is 6 to 12. An effective amount of a blend of low molecular weight brominated polystyrene to provide a blend of high impact polystyrene with flame retardancy at ⅛ inches in the UL-94 test, VO, wherein the low molecular weight brominated polystyrene has a degree of polymerization of 3 to 20, A flame retardant high impact polystyrene composition, wherein the amount of bromine is 53 to 76% by weight based on the total weight of brominated polystyrene. 7. Flame retardant high impact polystyrene composition according to claim 6, characterized in that the degree of polymerization is from 5 to 15. The flame retardant high impact polystyrene composition according to claim 7, wherein the amount of bromine is 61 to 71% by weight based on the total weight of the brominated polystyrene, and the degree of polymerization is 6 to 12. 9. Flame retardant high impact polystyrene composition according to claim 8, wherein the amount of bromine is 66 to 70% by weight, based on brominated polystyrene. The method of claim 1, wherein the low molecular weight brominated polystyrene is 3 to 20% by weight of the high impact polystyrene and the low molecular weight brominated polystyrene, the brominated polystyrene has a polymerization degree of 3 to 20, and the amount of bromine in the oligomer is 53 to 76 weight Polystyrene composition, characterized in that%. The polystyrene composition according to claim 10, wherein the amount of low molecular weight brominated polystyrene oligomer is 10 to 18% by weight. The polystyrene composition according to claim 11, wherein the polymerization degree is 5 to 15 and the amount of bromine in the oligomer is 61 to 71% by weight. The polystyrene composition according to claim 12, wherein the polymerization degree is 7 to 9 and the amount of bromine is 66 to 70% by weight. The polystyrene composition according to claim 1, wherein the physical property retention property is retained by correspondingly reducing the degree of polymerization while increasing the amount of bromine in the brominated polystyrene. The polystyrene composition according to claim 10, wherein the physical property retention property is retained by correspondingly reducing the degree of polymerization while increasing the amount of bromine in the brominated polystyrene. 13. The polystyrene composition according to claim 12, wherein the physical property retention property is retained by correspondingly reducing the degree of polymerization while increasing the amount of bromine in the brominated polystyrene. High impact polystyrene is melt blended with an effective amount of low molecular weight brominated polystyrene and 1 part by weight of antimony based synergist per 2 to 5 parts by weight of low molecular weight brominated polystyrene to provide a composition having excellent flame retardancy and excellent physical property retention properties of notched Izod. A method of making a flame retardant high impact polystyrene composition, comprising the steps of: 18. The process according to claim 17, wherein the amount of bromine in the polystyrene is 53 to 76% by weight based on the total weight of the brominated polystyrene. 18. The process according to claim 17, wherein the degree of polymerization of the brominated polystyrene is 3 to 20 and the amount of bromine is 61 to 71% by weight. 18. The method of claim 17, wherein the degree of polymerization is from 6 to 12.